That's because some of the Republicans who are running for the Senate are not saying whether they would back McConnell as their party leader - and one candidate is on record saying Kentucky's senior senator should quit while another has said he wants someone else.

There is a lot of jockeying among GOP candidates in a variety of races in which some are trying to distinguish themselves as not tied to the party establishment.

And you can't be more party establishment than leader of the Senate Republicans.

McConnell is seeking a sixth term, facing a primary challenge from Louisville businessman Matt Bevin, who has criticized the senator for, among other things, serving too long in Washington.

In other primaries around the nation, McConnell's name comes up from time to time. Reporters as well as political rivals seem to use support for the Kentuckian as leader as a measure of how close Republicans might track with him ideologically or whether he is a symbol of the party establishment some GOP candidates want to overthrow.

This happened to some extent in 2012 as well, after which McConnell was re-elected as GOP leader.

In some cases this year, Republicans again don't appear eager to get too close to McConnell.

For example, GOP Rep. Jack Kingston, one of a group of Republicans seeking a Senate seat in Georgia, was not saying whether he would support McConnell.

Asked about his preference by The Hill, a newspaper that covers Congress, Kingston campaign spokesman Chris Crawford said: "Jack Kingston is focused on communicating his record and his vision to the people of Georgia so we can elect a proven, tested conservative to turn back (Senate Majority Leader) Harry Reid's liberal agenda."

Another GOP candidate in the race, former Georgia Secretary of State Karen Handel, said earlier this month that the Republicans "need new leadership." McConnell's supporters "can make a determination for him," Handel told The Hill.

In Oklahoma, none of the three GOP Senate candidates would say they support McConnell, The Hill reports. One of them, state Sen. Randy Brogdon, called on McConnell to resign, saying the senator was to blame for the "growing scope of government."

Another one of the candidates, former Oklahoma House Speaker T.W. Shannon, was pressed by a Tulsa radio station on whether he would vote for McConnell as GOP leader.

"I don't know who all the options will be, but I'm going to vote for the guy that most resembles the values of the people who sent me there to govern. So, I don't know who all the options will be," Shannon said.

In Iowa, GOP Senate candidate Sam Clovis said last year that "I think we need a change in leadership in the United States Senate," according to The Sioux City Journal.

Nebraska Republican Senate candidate Ben Sasse lived up to his name, posting a YouTube video calling on McConnell "to show some real leadership."

John Ullyot, a Republican strategist and former Senate aide, told The Hill that "in this toxic environment, (GOP candidates) would not want to take any step that would make them less favorable to the Tea Party and others who are far right of center."

"If you look back four or six or eight years ago, you would not have seen this level of distancing on the part of Republican primary candidates, but it just shows how much these candidates are under pressure," Ullyot said.

Some Democratic Senate candidates also have been reluctant to say whether they would want Reid as their leader.

As Politico reported earlier this month, embattled Sen. Mark Begich, D-Alaska, was asked about supporting Reid and he replied: "My first job is to get re-elected."

Another Democratic senator up for re-election this year, New Hampshire's Jeanne Shaheen, said about Reid's return to leadership: "Oh, I'm not going to speculate on that."

Reid appears to have the backing of a broad portion of the Democratic caucus in the Senate, Politico reported.

To be sure, McConnell has many supporters as well, notably tea party movement leader and fellow Kentucky Sen. Rand Paul.

And the Republican leader is using his Bluegrass Committee to aid fellow GOP candidates.

Between Jan. 1, 2013 and the end of March, McConnell's PAC had given $325,000 to Republican candidates for the Senate and House, according to filings with the Federal Election Commission.